A known socket for electrical parts of the type mentioned above, as shown in FIGS. 14 to 16, includes an IC socket 2 for holding an IC package 1 as "electrical part".
Such IC package 1 is so-called a gull-wing type, in which a plurality of IC leads 1b as "terminals" project sideways from a package body la having substantially a square shape.
The IC socket 2 has a socket body 3 which is provided with a mount portion 3a on which the IC package 1 is mounted, and a plurality of contact pins 4 capable of being elastically deformable so as to be contacted to the IC leads 1b of the IC package 1 in electrically conductive state are also formed to the socket body 3. Each of these contact pins 4 has a stationary contact piece 4a contacting the lower surface side of the IC lead 1b of the IC package 1 and a movable contact piece 4b contacting the upper surface side of the IC lead 1b in a manner such that the IC lead 1b of the IC package 1 is clamped between the stationary and movable contact pieces 4a and 4b.
The socket body 3 is also provided with an upper operation member 5 to be vertically movable in the following manner in an operative state. That is, when the upper operation member 5 is lowered against the urging force or elastic force of the contact pins 4 and a spring means, not shown, the movable contact piece 4b of the contact pin 4 is elastically deformed and then separated from the IC lead 1b, and on the contrary, when the upper operation member 5 is moved upward, the movable contact piece 4b is returned by the elastic force to thereby press the IC lead 1b from the upper portion thereof so as to clamp the IC lead 1b between this movable contact piece 4b and the stationary contact piece 4a.
However, in the conventional socket of the structure mentioned above, when the IC socket 2 is mounted to a printed circuit board, not shown, if an external force is applied to the contact pin 4 from the lower side thereof, the contact pin 4 is raised upward as shown in FIGS. 15 and 16, and there may cause such defect that a position of a stationary contacting portion 4c of the stationary contact piece 4a is raised or inclined, which results in a deterioration of electrical conductivity to the IC lead 1b and a deformation thereof.
Accordingly, it is an object of the present invention is to provide a socket for electrical parts which is capable of preventing the contact pins from being raised and positioning the stationary contact pin and other elements in their correct positions.
Furthermore, although the conventional IC socket mentioned above adopts two-point-contact-type contact pins, an IC socket 6 shown in FIGS. 17 and 18 adopts one-point-contact-type contact pins 7.
The IC socket 6 has a socket body 8 having a mount portion 8a on which the IC package 1 having a rectangular shape is mounted and also having guide portions 8b at positions corresponding to the corner portions of the IC package 1 for positioning the IC package 1 to a predetermined position. Partition wall sections 8c are formed at the peripheral edge portion of the mount portion 8a so as to project upward and a plurality of slits 8d are formed to the partition wall sections 8c with predetermined pitches.
The socket body 8 is also formed with a plurality of elastically deformable contact pins 7 which are contacted to or separated from the IC leads 1b of the IC package 1. Each of the contact pins 7 has a movable contact piece 7a contacted to or separated from the upper surface of the IC lead 1b of the IC package 1, and these contact pins 7 are inserted into slits 8d, respectively, to be vertically movable, formed to the partition wall sections 8c.
Furthermore, as not shown in FIGS. 17 and 18, an upper operation member such as shown in FIG. 14 is provided for the socket body 8 to be vertically movable. When this upper operation member is lowered against urging force of a spring and contact pins 7, springy (elastic) portions of the contact pins 7 are elastically deformed thereby to separate the movable contact pieces 7a from the IC leads 1b, and on the other hand, when the upper operation member is raised, the springy portions are returned by their elastic force and the movable contact pieces 7a contact the upper surfaces of the IC leads 1b, as shown in FIG. 17, and press the IC lead 1b from the upper side thereof, thus establishing an electrical conduction between the contact pin 7 and the IC lead 1b.
However, in the conventional IC socket of the structure mentioned above, as the IC package has been made compact, a number of IC leads projecting from the package body have to be arranged with narrow pitch and narrow width. In other words, if the width of the IC lead 1b is not made narrow, it is impossible to arrange a number of IC leads 1b with a constant interval from each other. Accordingly, when such IC package 1 is mounted on the mount portion 8a of the socket body 8, the IC leads 1b, each having narrow width, intrude into the slits 8d formed to the partition wall sections 8c formed to the peripheral edge portion of the mount portion 8, resulting in the deformation or damage of the IC leads 1b and undesired mounting thereof.
Accordingly, another object of the present invention is to provide a socket for electrical parts having a structure capable of preventing terminals of electrical parts such as IC package from intruding into slits formed to the partition wall sections of the socket body and, hence, preventing the terminals from being deformed, damaged and undesirably mounted.